Fix imports when : is not in PYTHONPATH

[jmcarcell]

We rely on : being in PYTHONPATH, which means that Python will look into the current directory. This is important because we have steering files that either through ddsim or k4run exec other files that are in different directories. Without :, imports in the steering files from the current directory don't work. Since I am not sure that the best option is to always add : at the end of PYTHONPATH and the LCG stacks don't have it by default, let's fix it in the few places that it happens. It also improves using local packages since this is something that I have spent some time on in the past when setting my local environment and it wouldn't work.

BEGINRELEASENOTES

• CLDReconstruction.py, cld_arc_steer.py: Fix importing local files when local directory is not part of the PYTHONPATH due to : not being at the end of the PYTHONPATH variable.

ENDRELEASENOTES